A typical wireless communication system includes a number of base stations, each radiating to provide one or more coverage areas in which to serve user equipment devices (UEs) such as cell phones, tablet computers, tracking devices, embedded wireless modules, and other wirelessly equipped devices, whether or not user operated. In turn, each base station could connect with a core access network that includes entities such as a network controller, switches and/or gateways, and the core network could provide connectivity with one or more external networks such as the public switched telephone network (PSTN) and the Internet. With this arrangement, a UE within coverage of the system could engage in air interface communication with a base station and could thereby communicate via the base station with various remote network entities or with other UEs served by the base station.
Such a system could operate in accordance with a particular air interface protocol, examples of which include, without limitation, Long Term Evolution (LTE) (using orthogonal frequency division multiple access (OFDMA) and single-carrier frequency division multiple access (SC-FDMA)), Code Division Multiple Access (CDMA) (e.g., 1×RTT and 1×EV-DO), Global System for Mobile Communications (GSM), IEEE 802.11 (WIFI), and BLUETOOTH. In accordance with the protocol, each coverage area could operate on one or more carrier frequencies, with the air interface being structured to define various channels for carrying downlink communications from the base station to UEs and uplink communications from UEs to the base station. Further, the air interface protocol could define specific procedures for registration of UEs, handover of UEs, and other service of UEs.
For each coverage area of such a system, the base station that provides the coverage area could be equipped with an antenna that has a configured radio frequency (RF) beam direction. In particular, the antenna could be structured to provide a directional radiation pattern that has an azimuth defining the direction of radiation from true north in an x-y reference plane and perhaps an angle of elevation defining a direction of tilt with respect to the x-y reference plane.
The antenna could be physically configured to provide such a directional radiation pattern and could be oriented in a manner that points the radiation pattern in a desired direction, thus establishing the RF beam direction of the antenna. For instance, the antenna could be a phased array structure, having multiple antenna elements set to radiate with varying phase so as to cooperatively establish a directional radiation pattern (which could be electronically steered by adjusting the phases of respective antenna elements), and the phased array structure as a whole could be physically oriented in a manner that points the radiation pattern in a desired direction, thus establishing the RF beam direction of the antenna.
In practice, the RF beam direction of a base station antenna in such a system could be usefully factored into determining the geographic location of a UE served by the system.
For example, when a UE is served by a base station whose antenna has a particular azimuth, the angle of arrival of uplink transmission from the UE to the base station (as determined based on phase differences at antenna elements in the x-y plane for instance) could be offset from the antenna's azimuth to establish the absolute bearing of the UE's position from the base station's position. Given this absolute bearing, given a known geographic location of the base station, and given a distance between the UE and the base station (as determined based on signal delay between the UE and the base station), the UE's geographic location could be computed.
As another example, the wireless system could include a mobile location center (MLC) that is configured to determine and report location of a UE based on consideration of UE-received transmissions from multiple base stations. For instance, when the MLC seeks to determine the UE's location, the MLC could prompt the UE to measure and report signal delay from each of multiple base stations from which the UE detects coverage, and the system could then compute the UE's location based on the reported signal delay measurements and based on knowledge of each base station's azimuth as well as possibly other factors.